This invention relates to a high voltage powerline sensor device.
Monitoring conditions in or about a.c. powerlines, in both overhead and underground and primary and secondary applications, is a useful practice for electric utility companies in order to anticipate outages which occur due to faulty equipment and overloads on a.c. powerlines and which result in loss of service for potentially large numbers of customers. The potential for an outage and for loss of the greatest number of customers is increased during peak periods when power usage is at a maximum and delivery of continuous power is most critical. Outages caused by faulty and overloaded lines, transformers and other equipment are expensive to repair, dangerous for utility company employees, and costly to the electric utility company in terms of income lost for lost service and in terms of damage to the ultility""s reputation.
Thus, a.c. powerline sensors which sense electrical conditions, such as power, voltage and current are very useful to electric utility companies in monitoring a.c. powerlines and associated equipment, such as transformers and switches, in order to better anticipate the likelihood of an unexpected outage occurring. The sensors allow the utility to monitor the conditions on the powerlines, and thus the sensors facilitate maintenance on and replacement of powerlines which are likely to become de-energized as a result of an overload or fault, thereby lowering the number of unexpected outages.
In order to perform this monitoring most efficiently, a communications link is typically established between each sensor on the system being monitored and a remote base station. This allows the utility company to monitor all of its sensors in one remote location instead of having to individually check each sensor in situ. One method of establishing a communications link is achieved by transmitting signals to a local ground station by means of, for example, an FM radio link. The signals are then transmitted to a remote central monitoring location via, e.g. radio, land lines or satellite channels. See U.S. Pat. No. 4,786,862 to Sieron.
Directly tapping the high-voltage powerline involves extensive work with the powerline de-energized to assure worker safety. Also, directly-connected sensing devices must be insulated against the high-voltage being carried in the powerlines typically resulting in an expensive sensor requiring significant effort to install.
Accordingly, it is an object of this invention to provide a high voltage powerline sensor.
It is a further object of this invention to provide such a high voltage powerline sensor which is more accurate than prior art powerline sensors.
It is a further object of this invention to provide such a high voltage powerline sensor which is not susceptible to the effects of adverse weather elements.
It is a further object of this invention to provide such a powerline sensor which is not susceptible to unknown and/or variable voltages induced in the sensor.
It is a further object of this invention to provide such a powerline sensor which is easy to assemble, construct, and install.
It is a further object of this invention to provide such a powerline sensor which can be attached to the powerline without de-energizing the powerline and without the need to directly trap the powerline.
This invention results from the realization that a more effective powerline sensor useful for, among other applications, low current, high voltage powerlines can be effected 1) by a housing with an apex and sloping sides which divert adverse whether elements which could otherwise affect voltage measurements, 2) by making the housing conductive and connecting it to the powerline to produce a faraday cage impervious to outside interference and to insure that an unknown and/or variable voltage is not induced in the housing, and 3) by the use of the number of physically discrete but electrically interconnected voltage sensing devices spaced about the periphery of the housing.
This invention features a powerline sensor comprising a housing physically and electrically connectable to a powerline and a plurality of voltage sensing devices spaced peripherally about the housing. Each voltage sensing device typically includes an outer plate, an inner plate, and a dielectric material between the inner and outer plates. The inner plates are electrically connectable to the powerline, the outer plates are electrically isolated from the power line. There are also means for sensing the voltage potential between the inner and outer plates. Alternatively, the function of the inner plates may be performed by the housing itself and thus the inner plates eliminated.
The inner and outer plates of all voltage sensing devices are preferably connected in series.
The inner plates are typically electrically connected to the powerline via a connection between an inner plate and the housing. The housing has n sides (e.g., 4) and n voltage sensing devices, one sensing device per side.
The preferred powerline sensor housing has a apex and sloping sides for diverting adverse weather elements. The housing is typically metal with an insulative coating thereon. The voltage sensing devices are usually secured to outer insulative coating of the metal housing. Further included may be a protective material over the outer plate of each voltage sensing device.
The housing is preferably black and the inner and outer plates of each voltage sensing device are typically copper foil. Further included may be means for transmitting the voltage potential sensed to a location remote from the sensor. A pair of spaced jaws on the housing are operable between an open position and a position closed about the powerlines for physically and electrically connecting the housing to the powerline.
Therefore, in one embodiment, the powerline sensor of this invention includes a housing attachable to a powerline, a plurality of voltage sensing devices spaced peripherally about the housing, each voltage sensing device including an outer plate, an inner plate, and a dielectric material between the inner and outer plates, the inner plates electrically connectable to the powerline and electrically connected to each other, the outer plates electrically isolated from the power line and electrically connected to each other and means for sensing the voltage potential between the inner and outer plates.
More broadly stated, this invention features a powerline sensor comprising a housing having n sides, a plurality of n voltage sensing devices, one voltage sensing device per side, each voltage sensing device including an outer plate, an inner plate, and a dielectric material between the inner and outer plates; and means for sensing the voltage potential between the inner and outer plates.
Even more broadly, the powerline sensor of this invention comprises a housing electrically connected to a powerline, the housing having an apex for diverting adverse weather elements; and a plurality of voltage sensing devices spaced peripherally about the housing.
Each voltage sensing device typically includes an outer plate, an inner plate, and a dielectric material between the inner and outer plates, the inner plates are electrically connectable to the powerline, the outer plates electrically isolated form the powerline. The outer plates of all voltage sending devices are connected in series. The inner plates are electrically connected to the powerline via a connection between an inner plate and the housing. The housing may have n (e.g., 4) sides and n voltage sensing devices, one sensing device per side.
The housing is preferably made of metal and has an insulative coating thereon. The voltage sensing devices are usually secured to the outer insulative coating of the metal housing. The housing is usually black and the inner and outer plates of each voltage sensing device are usually copper foil.
In the broadest sense, the invention thus features a housing physically and electrically connectable to a powerline, at least one voltage sensing device on the housing, an insulating (e.g. dielectric) material between the voltage sensing device and the housing, and a circuit or some other means for determining the voltage on the powerline.